40. An element has the configuration [He]2s^2.
a. Which element is it?- Beryllium
b. Is it metal or nonmetal?- metal
c. How many valence (or outer shell) electrons does it have?- 2 valence electrons.
Is this correct?
Thanks
-MC
Yes, yes, yes.
go to the head of the class.
:D
-MC
Yes, your answers are correct!
To arrive at these answers, here's how you can explain it:
a. The element with the electron configuration [He]2s^2 is Beryllium (Be). The [He] represents the noble gas configuration of helium, which means that the electron configuration of beryllium starts from where the helium configuration left off. In this case, it starts with a filled 1s orbital (which contains 2 electrons) and then adds 2 more electrons to the 2s orbital.
b. Beryllium is a metal. Metals are typically found on the left side of the periodic table, and beryllium falls under the group 2 elements (also known as the alkaline earth metals). Metals tend to have a shiny appearance, are good conductors of heat and electricity, and are generally malleable and ductile.
c. Beryllium has 2 valence (or outer shell) electrons. Valence electrons are the electrons in the outermost shell of an atom. In the case of beryllium, the outermost shell is the 2s orbital, and there are 2 electrons present in it. Valence electrons play a crucial role in determining an element's chemical properties and how it interacts with other elements.